Centrifuge with blood sample holding means

ABSTRACT

A CENTRIFUGE WITH A ROTOR ADAPTED TO SIMULTANEOUSLY HOLD AND CENTRIFUGE A PLURALITY OF BLOOD SEPARATION TUBES AND HEMATOCRIT TUBES, ALSO PROVIDED WITH SPEED CONTROL OVER A WIDE RANGE, FROM 4,000 R.P.M. FOR URINE SPECIMEN CENTRIFUGATION, UP TO 10,000 R.P.M. FOR RAPID HEMATOCRIT PREPARATION, ALSO PROVIDED WITH A PROTECTIVE LID LATCH CORRELATED WITH A COMBINED BRAKE ACTUATOR AND CIRCUITOPENING SWITCH TO CUT OFF POWER WHEN THE LID IS LIFTED.

March 13, 1973 ALLEN I 3,720,368

CENTRIFUGE WITH BLOOD SAMPLE HOLDING MEANS Filed July 15, 1971 4 n a: ii 2 A i i n 1 v d I a I n k I D/PEK P. ALLEN g a a United States Patent3,720,368 CENTRIFUGE WITH BLOOD SAMPLE HOLDING MEANS Derek R. Allen,Corona del Mar, Calif., assignor to Bio-Dynamics, Inc., Santa Ana,Calif. Filed July 15, 1971, Ser. No. 162,829 Int. Cl. B04b 9/12 US. Cl.233--26 12 Claims ABSTRACT OF THE DISCLOSURE A centrifuge with a rotoradapted to simultaneously hold and centrifuge a plurality of bloodseparation tubes and hematocrit tubes; also provided with speed controlover a wide range, from 4,000 r.p.m. for urine specimen centrifugation,up to 10,000 r.p.m. for rapid hematocrit preparation; also provided witha protective lid latch correlated with a combined brake actuator andcircuitopening switch to cut off power when the lid is lifted.

BACKGROUND OF THE INVENTION Blood separation centrifuges and hematocritpreparacentrifuges are individually well known and in common usage asseparate devices. None of them have combined both blood separation andhematocrit preparation in a simultaneous combined operation. Thoseheretofore available have had a maximum r.p.m. limit of 8,000. Acentrifuge operable at variable graduated speeds over a wide rangesuitable both for low speed urine preparation and high speed rapid bloodseparation, has not hitherto been available. There has hitherto been noprovision for simultaneous lid latch release, braking and power cutoff.

SUMMARY OF THE INVENTION The invention provides a rotor having asegmental upper face of flat ring form, the segments being separated bya plurality of shallow radial slots adapted to hold respectivehematocrits in an annular array in a common plane of rotation, the innerends of the hematocrits bridging over a central cavity to the rotor hub,where they are held down by engagement in an annular retainer groove.Between the hematocrit slots, in the central cavity, are an equal numberof diagonal sockets, equally spaced circumferentially, to receive andhold a plurality of blood separation tubes in a conical array, theiropen ends facing inwardly and their bottoms outwardly. There are twelveof the sockets, making it possible to centrifuge two, three, four, six,eight, nine, ten or twelve tubes simultaneously in a balanced,vibration-free array. The apparatus is provided with a Wide-range speedcontroller and with a voltage regulator correlated with the speedcontroller in a manner to provide accurate r.p.m. readings throughoutthe range of speeds. A brake, operable on the rotor rim, has apushbutton actuator which also functions to release a lid latch. Inimmediate response to the latch release, the lid, which is springloaded, will be raised sufiiciently to open the power circuit so as tocut off the power when the brake is applied.

OBJECTS OF THE INVENTION The general object of the invention is toprovide a laboratory centrifuge of improved versatility of function andrapidity of operation, capable of replacing several differentcentrifuges of older types. Specific objects are to provide acentrifuge:

(1) having a twelve tube capacity;

(2) adaptable to vacuum tubes;

(3) having a twelve hematocrit capacity;

(4) operable to centrifuge twelve tubes and twelve hematocritsconcurrently;

3,7236% Patented Mar. 13, 1973 These and other objects will becomeapparent in the following specifications and appended drawings, wherein:

FIG. 1 is a front perspective view of a centrifuge embodying theinvention, the lid being shown in an open position;

FIG. 2 is a transverse sectional view of the rotor and associated parts,taken on line 22 of FIG. 1;

FIG. 3 is a detail sectional view through the rotor top, taken on line33 of FIG. 1;

FIG. 4 is a detail sectional view of the latch-brake unit, taken on line44 of FIG. 1;

FIG. 5 is a plan view of the latch-brake unit, with the latch keepershown in horizontal section as indicated by line 5-5 of FIG. 4, and

FIG. 6 is a plan view of the latch cover.

DESCRIPTION Referring now to the drawings in detail, I have showntherein, as an example of one form in which the invention may beembodied, a centrifuge embodying, in general, a casing A having a hingedlid B, a rotor chamber C mounted in the top of easing A, a rotor Dmounted on the shaft of a motor E (shown schematically) a speedcontroller F and a timer G arranged in a common control box at the footof easing A, and a combined latch and brake H in the front of the casingA at its top.

Casing A has a body 10', an outwardly offset rim 11 to receive andsupport the rotor chamber C, and a control box 12 at its foot. Motor Eis mounted in the lower portion of easing body 10 in a suitable mannerof conventional nature (not illustrated).

Rotor chamber C comprises a bowl-shaped body 15 having a domed reentrantbottom 16 with a central opening 17, and a top flange 18 of squareperiphery to fit snugly within the offset rim 11 of easing A in flushrelation to the top of the rim. Body 15 is of a high strengthplasticmaterial or equivalent, and of suificient wall thickness to contain therotor D in the event of fragmentation thereof while rotating at highspeed. In the forward side of top flange 18 is a forwardly projectingpocket 19 to hold the brake-latch unit H.

Rotor D comprises, in general, a bowl-shaped body 21 and a head 22. Body21 has a generally cylindrical lateral wall 23 and a frusto-conicalreentrant bottom 24 having a flat inner lip 25 defining a centralopening. Head 22 has a hub 26 with a bottom extension fitted in theopening within lip 25, a bottom web 27A just above such bottomextension, resting on lip 25, a frusto-conical rack web 27 flaringupwardly and outwardly, a flat top annulus 28 extending radiallyoutwardly from the upper extremity of web 27, and a thick rim 29 havingin its underside a cylindrical groove snugly receiving the rim of bodywall 23.

In the intermediate web 27 are twelve tube rack sockets 30 in the formof cylindrical openings having respective downwardly and outwardlyinclined diagonal axes collectively arranged in a conical array coaxialwith the rotor axis. Blod sample tubes 31 are snugly receivable in therespective sockets 30 in a downwardly flaring conical array, theirbottoms extending into the annular trough defined between lateral wall23 and bottom 24 of rotor body 21. Tubes 31 have rim flanges 32 whichseat against the upper, inner surface of frusto-conical web 27 toposition the tubes in balanced array as they are pulled outwardly bycentrifugal force.

Top annulus 28 is provided with twelve shallow radial slots 34 forreceiving and positioning respective hematocrits 35 of fine, tubularquill form, with closed outer ends and inner ends which are originallyopen but are closed by respective wax plugs after being filled withrespective blood samples. Their outer ends, under centrifugal force,will engage against a cushioning ring 36 of suitable resilient material,which in turn is supported within an annular upstanding lip 37 on coverrim 29. Thus the hematocrits are supported against radial movementduring centrifuging. Their inner ends are received in a retaining groove38 in the upper end of rotor hub retainer screw 40, slightly above theplane of their outer ends, whereby the hematocrits are tilted slightlyinto a flat conical, with an apex above the plane of their outer ends,just high enough so that centrifugal force, tending to push themradially outwardly and thus to tilt them to higher inclination, willhold their inner ends against an annular shoulder 39 overhanging theretaining groove 38. Shoulder 39 is formed as a radial flange onretainer screw 40 threaded into a reduced tip 41 on the upper end of themotor shaft 42 of motor E. Screw 40 has a radial flange 43 which bearsagainst the upper end of rotor hub 26, and secures the rotor D to shaft42. The retaining groove 38 is of a satisfactory axial width to looselyreceive the inner ends of the hematocrits and the shoulder 39 is locatedso as to position them at a satisfactory angle of inclination.

Latch-brake unit H comprises a slide 46 mounted in pocket 19 for radialsliding movement, having on its rear end a push button 47 projectingthrough an opening in pocket 19, and on its forward end a brake shoe 48contoured for braking engagement with the periphery of rotor head rim29. A bow spring 49, having end loops 53 mounted on pegs 54 dependingfrom a latch cover 55 and its middle bowed and yieldably abutting acentral projection 50 on slide 46 on the forward side of button 47,loads the slide 46 for retraction to the brake-release position shown inFIG. when the button 47 is released. In this retracted position a latchfinger 51 projecting rearwardly from shoe 48, makes latching engagementwith a keeper loop 52 depending from the rim of lid B, to hold the lidin a closed position as shown in FIG. 4. Latch cover 55 is shown in FIG.6 but is omitted from FIG. 1 for clarity.

Lid B has a downwardly projecting peg 60 which, when the lid is closed,projects into an opening in rotor chamber top flange 18, engages aspring-loaded plunger 56 in such opening, and depresses the plunger toclose a normally open switch 57 in the power circuit 58 of motor B,thereby activating the circuit so that motor B may drive the rotor Dunder control of speed controller F and timer G. Then the latch isreleased, the lid B will pop up under the spring loading of plunger 56.The upward movement of the plunger will simultaneously release switch 57for selfopening movement, thereby cutting off the power, and at the sametime a light pressure on push button 47 will gently brake the spinningrotor D.

Lid B has a circular inspection glass 61 and a hematocrit scale 62inscribed thereon.

Speed controller F utilizes a solid-state potentiometer P to vary thecurrent supplied to the motor, under the regulating control of voltageregulator VR, from a current source V.

I claim:

1. In a laboratory centrifuge:

a rotor disposed on a vertical axis of rotation, said rotor including ahead comprising a hub, a bottom web encircling said hub, a non-radialannular rack web carried by said bottom web and flaring upwardly andoutwardly therefrom, and a flat top annulus extending outwardly from theperiphery of said rack web at the top plane thereof;

a plurality of tube sockets in said rack web, disposed in acircumferential array on respective axes directed outwardly so as tohold respective blood separation tubes having inwardly directed mouthsand outwardly projecting bottoms;

a plurality of hematocrit holding radial slots in the upper face of saidtop annulus, in a plane above the mouths of said tubes as mounted insaid rack web;

a plurality of hematocrits in said slots;

and means to retain said hematocrits in said slots during high speedrotation of said rotor;

said bottom web and rack Web defining a dished space which is open tothe top plane of said annulus at all times.

2. A centrifuge rotor as defined in claim 1:

said rack web being of frusto-conical bowl shape;

said sockets consisting of openings in said web, their axes beingarranged in a downwardly flaring conical array;

said sockets being disposed so as to position the mouths of said tubesbelow the plane of said hematocrit holding slots.

3. A centrifuge rotor as defined in claim 2:

said rotor further including a bowl shaped body including a generallycylindrical lateral wall secured at its upper margin to said head;

and a reentrant frusto-conical bottom tapering upwardly and inwardly andsecured to said hub;

said body defining an annular space of acute angular cross-section intowhich said tubes extend when mounted in said sockets.

4. A centrifuge rotor as defined in claim 3:

the bottoms of said tubes being closely adjacent said reentrant bottomand said lateral wall when mounted in said sockets.

5. A centrifuge as defined in claim 1, including:

a casing in which said rotor is mounted, including a hinged lid forcovering said rotor when the rotor is in operation;

said dished space being fully open upon opening said lid and removingsaid hematocrits, so as to provide immediate access to said bloodseparation tubes.

6. A centrifuge as defined in claim 1:

said hub extending upwardly from said bottom web;

said means to retain said hematocrits comprising a retainer screw havinga radial flange defining the lower side of an annular groove in saidscrew, in which the inner ends of the hematocrits are loosely received;

and a drive motor shaft on the upper end of which said hub is mounted,said screw being anchored in said upper end of the shaft and securingsaid hub thereto.

7. In a laboratory centrifuge:

a housing having a top opening;

a rotor rotatably mounted in said housing on a vertical axis, said rotorincluding a tube-holding head and having a circular rim disposed in saidopening;

a cover hinged to a back side of said housing for upward openingmovement of its front side;

a latch element depending from said front side of the cover;

and a latch-brake unit comprising a slide mounted in said housing in thetop front area thereof, for movement radially toward said rotor rim andhaving an outer end manually engageably for inward projection thereof;

a cooperating latch part carried by said slide and having latchingengagement with said latch element in a normal outwardly retractedlatching position of said slide and releasably upon inward projectionthereof;

and a brake element mounted on said slide in opposed relation to saidrotor rim, for braking engagement with said rim upon latch-releasinginward projection of said slide.

8. A centrifuge as defined in claim 7:

and means yieldingly biasing said slide for movement to said latchingposition.

9. A centrifuge as defined in claim 8:

said housing including a top front pocket in which said slide isslidably received;

said slide including at its outer end a push button and a taperingprojection inwardly of said push button;

said biasing means comprising a bow spring extending in a generallycircumferential direction with its ends anchored to the housing near thesides of said pocket and its mid-portion engaged under flexure againstsaid projection to exert outward pressure thereagainst.

10. In a laboratory centrifuge:

a rotor disposed on a vertical axis of rotation, said rotor including ahead comprising a hub, a non-radial annular rack web carried by said huband extending outwardly and upwardly therefrom, and a flat top annulusextending outwardly from the periphery of said rack web at the top planethereof;

a plurality of tube sockets in said rack web, disposed incircumferential array on respective axes directed outwardly so as tohold respective blood separation tubes having inwardly directed mouthsand outwardly projecting bottoms;

a plurality of hematocrit holding radial slots in the upper face of saidtop annulus;

a plurality of hematocrits in said slots;

means carried by said head for supporting the inner ends of saidhematocrits at a height slightly above the height of the outer endsthereof when resting in said slots, whereby said hematocrits will bedisposed in an annular array of shallow conical form, inclined upwardlytoward the center thereof;

retaining means overhanging the inner ends of the hematocrits whenresting on said supporting means, to restrain said inner ends fromlifting movement in response to centrifugal force;

and means for abutting engagement with the outer ends of saidhematocrits to restrain them from radially outward movement in responseto said centrifugal force.

11. A centrifuge as defined in claim 10:

said abutting engagement means being free of any obstruction of upwardmovement of the outer ends of said hematocrits when the rotor isstopped, whereby the hematocrits may be removed by lifting their outerends clear of said abutting engagement means and then withdrawing theirinner ends from beneath said overhanging retaining means.

12. A centrifuge as defined in claim 11:

said abutting engagement means comprising a cushioning ring having acylindrical internal face engaged by said hematocrits;

and an annular upstanding lip on said head at the periphery of said topannulus, said lip surrounding and providing radial support for saidring;

said supporting means and retaining means for the inner ends of thehematocrits being embodied in and defining an annular groove in aretainer element on the upper end of said rotor hub.

References Cited UNITED STATES PATENTS 3,133,882 5/1964 Mitchell et al233-26 3,168,473 2/1965 Goda et al. 233-26 3,567,113 3/1971 Stansell eta1 233-26 3,240,425 3/1966 Ray et a1 233-1 R 2,908,907 10/1959Danielsson 233-26 JORDAN FRANKLIN, Primary Examiner G. H. KRIZMANICH,Assistant Examiner US. Cl. X.R.

